1. Field of the Invention
This invention relates to a fastener for plates effective for use, for example, in mounting a trim board on the inner surface of a vehicle passenger compartment.
2. Prior Art Statement
A commonly used conventional fastener for mounting a vehicle trim board comprises a head portion and a leg portion projecting from the head portion. The trim board is secured to an inner wall of the passenger compartment by mounting the head portion on the trim board and engaging the leg portion in a mounting hole formed in the inner wall of the vehicle.
Referring to FIG. 1, in a known structure for mounting a fastener on a trim board, a trim board 10 is provided with a first hole 11 having a large diameter and a second hole 12 having a small diameter, the first and second holes being communicated with each other.
In mounting the conventional fastener on the trim board 10, the head portion is once inserted in the first large hole 11, and is then moved into the second hole 12 along the outer surface of the trim board 10 thereby to permit the head portion to be retained by the trim board 10.
However, this structure for mounting a fastener to a trim board has a shortcoming in that complicated machining is required to make the special configurations of the mounting holes 11 and 12. Furthermore, since it is difficult to tightly mount the head portion of the fastener in the small hole 12, play is likely to occur between the fastener and the trim board. The result is that the head portion of the fastener may accidentally move from the small hole 12 to the large hole 11 and become detached from the large hole 11. When this happens, the trim board 10 mounted on the inner surface of the passenger compartment comes loose and may, in some cases, become completely detached and fall off the inner wall when subjected to a shock. In addition, since the large hole 11 remains open after the trim board is mounted, dust etc. is likely to enter through the large hole 11.
Japanese Utility Model Publication No. 47-39170 discloses a fastener for mounting a trim board, in which the head portion has a special configuration and is mounted on the trim board with a rotating action. However, the overall configuration of the fastener is complicated and play between the trim board and the fastener is not eliminated.